For some types of home appliances it is important to have a user detection or recognition functionality, so than an appliance can recognize who is using it, in order to enable e.g. personalization and authorization features. For example, it is hereby possible to activate a user specific user profile. Similarly, it also possible to increase the safety level, e.g. by restricting the use for children for hazardous equipment, such as stoves and ovens, or restrict the access to certain compartments, such as e.g. the inner compartment of a wine refrigerator. It is also possible to restrict the use of the household appliance for certain persons or groups of persons, and/or to restrict the use of the household appliance during certain time periods.
Further, many types of biometric person-identifying devices and methods are per se known, based e.g. on the person's fingerprint, voice characteristics or iris pattern. Among the existing methods of person identification, fingerprint recognition is the cheapest, most accurate and feasible. For sensing fingerprint patterns, various techniques have been relied on, such as optical imaging techniques, thermal sensing, pressure sensing, capacitive sensing and skin resistance sensing. However, essentially all available fingerprint sensors require a direct contact between the user's finger and the sensor. However, such solutions, with an “open” sensor area, is not suitable for household appliances, since this impairs the protection provided by the casing of the appliance.
WO 00/46756 discloses a household appliance, and in particular a washing machine, provided with an authorization control including a fingerprint sensor. The fingerprint sensor is of a type comprising an external sensing area, which is to be contacted by the finger, which presumably makes the sensing device rather expensive. However, the arrangement of the fingerprint sensor on the exterior surface of the casing of the household appliance impairs the impermeability of the appliance, and requires modifications of the construction of an appliance. Hereby, the appliance becomes less protected from the surrounding environment. Still further, by means of this access control, the use of the household appliance becomes more difficult and tedious for the user.
US 2005/0151620 discloses a similar approach, where access to a refrigerator or freezer is controlled by means of a biometric person-identifying device, and primarily a voice-recognition device. Further, EP 0 949 578 discloses a household appliance with a fingerprint scanner for access control. US 2004/0160335 also discloses a household appliance with an authorization control, wherein a fingerprint sensor with a capacitive sensing area is used. However, all these known apparatuses are affected with similar drawbacks and shortcomings as the first one discussed.
Consequently, there is a need for a household appliance with a person-identification device, which is easy to use, rather inexpensive to manufacture, and where does the person-identification device does not significantly deteriorate other aspects of the household appliance, such as the impermeability of the casing.